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.TH CLOCK_NANOSLEEP 3C "Feb 5, 2008"
.SH NAME
clock_nanosleep \- high resolution sleep with specifiable clock
.SH SYNOPSIS
.LP
.nf
#include <time.h>

\fBint\fR \fBclock_nanosleep\fR(\fBclockid_t\fR \fIclock_id\fR, \fBint\fR \fIflags\fR,
     \fBconst struct timespec *\fR\fIrqtp\fR, \fBstruct timespec *\fR\fIrmtp\fR);
.fi

.SH DESCRIPTION
.sp
.LP
If the flag \fBTIMER_ABSTIME\fR is not set in the \fIflags\fR argument, the
\fBclock_nanosleep()\fR function causes the current thread to be suspended from
execution until either the time interval specified by the \fIrqtp\fR argument
has elapsed, or a signal is delivered to the calling thread and its action is
to invoke a signal-catching function, or the process is terminated. The clock
used to measure the time is the clock specified by \fIclock_id\fR.
.sp
.LP
If the flag \fBTIMER_ABSTIME\fR is set in the \fIflags\fR argument, the
\fBclock_nanosleep()\fR function causes the current thread to be suspended from
execution until either the time value of the clock specified by \fIclock_id\fR
reaches the absolute time specified by the \fIrqtp\fR argument, or a signal is
delivered to the calling thread and its action is to invoke a signal-catching
function, or the process is terminated. If, at the time of the call, the time
value specified by \fIrqtp\fR is less than or equal to the time value of the
specified clock, then \fBclock_nanosleep()\fR returns immediately and the
calling process is not suspended.
.sp
.LP
The suspension time caused by this function can be longer than requested
because the argument value is rounded up to an integer multiple of the sleep
resolution, or because of the scheduling of other activity by the system. But,
except for the case of being interrupted by a signal, the suspension time for
the relative \fBclock_nanosleep()\fR function (that is, with the
\fBTIMER_ABSTIME\fR flag not set) will not be less than the time interval
specified by rqtp, as measured by the corresponding clock. The suspension for
the absolute \fBclock_nanosleep()\fR function (that is, with the
\fBTIMER_ABSTIME\fR flag set) will be in effect at least until the value of the
corresponding clock reaches the absolute time specified by \fIrqtp\fR, except
for the case of being interrupted by a signal.
.sp
.LP
The use of the \fBclock_nanosleep()\fR function has no effect on the action or
blockage of any signal.
.sp
.LP
The \fBclock_nanosleep()\fR function fails if the \fIclock_id\fR argument
refers to the CPU-time clock of the calling thread. It is unspecified if
\fIclock_id\fR values of other CPU-time clocks are allowed.
.SH RETURN VALUES
.sp
.LP
If the \fBclock_nanosleep()\fR function returns because the requested time has
elapsed, its return value is 0.
.sp
.LP
If the \fBclock_nanosleep()\fR function returns because it has been interrupted
by a signal, it returns the corresponding error value. For the relative
\fBclock_nanosleep()\fR function, if the \fIrmtp\fR argument is non-null, the
timespec structure referenced by it is updated to contain the amount of time
remaining in the interval (the requested time minus the time actually slept).
If the \fIrmtp\fR argument is NULL, the remaining time is not returned. The
absolute \fBclock_nanosleep()\fR function has no effect on the structure
referenced by \fIrmtp\fR.
.sp
.LP
If \fBclock_nanosleep()\fR fails, it shall return the corresponding error
value.
.SH ERRORS
.sp
.LP
The \fBclock_nanosleep()\fR function will fail if:
.sp
.ne 2
.na
\fB\fBEINTR\fR\fR
.ad
.RS 11n
The \fBclock_nanosleep()\fR function was interrupted by a signal.
.RE

.sp
.ne 2
.na
\fB\fBEINVAL\fR\fR
.ad
.RS 11n
The \fIrqtp\fR argument specified a nanosecond value less than zero or greater
than or equal to 1,000 million; or the TIMER_ABSTIME flag was specified in
\fIflags\fR and the \fIrqtp\fR argument is outside the range for the clock
specified by \fIclock_id\fR; or the \fIclock_id\fR argument does not specify a
known clock, or specifies the CPU-time clock of the calling thread.
.RE

.sp
.ne 2
.na
\fB\fBENOTSUP\fR\fR
.ad
.RS 11n
The \fIclock_id\fR argument specifies a clock for which \fBclock_nanosleep()\fR
is not supported, such as a CPU-time clock.
.RE

.SH ATTRIBUTES
.sp
.LP
See \fBattributes\fR(7) for descriptions of the following attributes:
.sp

.sp
.TS
box;
c | c
l | l .
ATTRIBUTE TYPE	ATTRIBUTE VALUE
_
Interface Stability	Committed
_
MT-Level	MT-Safe
_
Standard	See \fBstandards\fR(7).
.TE

.SH SEE ALSO
.sp
.LP
.BR clock_getres (3C),
.BR nanosleep (3C),
.BR pthread_cond_timedwait (3C),
.BR sleep (3C),
.BR attributes (7),
.BR standards (7)
